Notes

Outline

Tuning the Redo Log Buffer

Objectives After completing this lesson, you should be able to do the following: Determine if processes are waiting for space in the redo log buffer Size the redo log buffer appropriately Reduce redo operations

The Redo Log Buffer

Sizing the Redo Log Buffer LOG_BUFFER parameter Default value: OS-specific, generally four times the maximum block size

Tuning the Redo Log Buffer

Diagnostic Tools for Tuning the Redo Log Buffer V$SESSION_WAIT Log Buffer Space event

Guidelines The Redo Buffer Allocation Retries value should be near 0; the number should be less than 1% of Redo Entries.

Guidelines

Reducing Redo Operations Fewer redo operations require fewer redo entries and thus less redo log buffer space. Some ways of reducing the redo entries are: Direct Path loading without archiving Direct Path loading with archiving using NOLOGGING mode Direct Load INSERT in NOLOGGING mode Using NOLOGGING mode in SQL statements

Summary In this lesson, you should have learned how to: Tune log buffer space Redo buffer allocation retries Size the redo log buffer appropriately Reduce redo operations with the NOLOGGING attribute